This invention relates to a pressure-reducing regulator for compressed natural gas (CNG), and more particularly to an improved CNG regulator for vehicular engines.
In U.S. Pat. No. 5,285,810, issued Feb. 15, 1994, there is described a pressure-reducing regulator having a balanced valving element arrangement with minimal friction drag. The valving element cooperates with internal structure to provide seating and sealing areas between high and low pressures of the natural gas, and the magnitudes and directions of the differential pressures are balanced at the seating and sealing areas.
U.S. Pat. No. 5,381,819, issued Jan. 17, 1995, was a division of application Ser. No. 08/016,376 which issued as U.S. Pat. No. 5,285,810. In this patent there is described another embodiment of the balancing valve in which the natural gas can flow directly to an outlet port rather than have the gas work against the diaphragm. This is beneficial where there are high flow rates of the natural gas and the possibility of diaphragm oscillation or instability.
In application Ser. No. 08/230,587, filed Apr. 21, 1994, which was a continuation-in-part of copending application Ser. No. 08/143,010, now U.S. Pat. No. 5,381,819, there is described a regulator having a valving element that is positively tied to the pressure-sensing and pressure-responsive diaphragm. The arrangement permits relative angular displacement between the valving element and the diaphragm and prevents cocking of the element in its axial movement. This regulator arrangement, although an efficient and uncomplicated design and effective in vehicle applications, may under certain flow rates generate an unwelcomed low level audible noise. While such a noise does not effect performance, reliability, or safety, it could raise an unnecessary concern for the vehicle operator.
Accordingly, the potential for audible noise generation which could arise under certain regulator conditions is eliminated by the improved regulator of the invention.